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Dying California trees raise wildfire risk

If you don't know what to look for, you might not notice the dying pine trees along the road in Idyllwild, Calif. If a tree's leaves are fading from green to brown, that probably means it's being eaten alive

Dying California trees raise wildfire risk

As California's drought worsens, the potential for wildfires rise. The state has lost more than 12 million trees since the drought began.
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The brown needles on these pine trees in Idyllwild on May 12, 2015 indicate a bark beetle infestation. The long drought has weakened the trees’ natural defenses, making them vulnerable to the pests.(Photo: Richard Lui/The Desert Sun)

If you don't know what to look for, you might not notice the dying pine trees along the road in Idyllwild, Calif. If a tree's leaves are fading from green to brown, that probably means it's being eaten alive by bark beetles — and California's epic drought is largely to blame.

Across Southern California, trees are dying in unusually high numbers as the drought continues. Water-starved vegetation is finding it harder to stay alive, and many pine trees in the mountains surrounding Southern California's Coachella Valley don't have the strength to fight off bark beetles.

It's a potent combination that could stoke devastating wildfires over the next few months.

"Fires are going to burn more actively if we have fire in an area where there's a lot more dead fuels," said Tom Rolinski, a meteorologist and fire specialist at the U.S. Forest Service in Riverside. "Everything's just coming together for us to see a potentially busy fire season."

Pat Boss, the project manager for the Mountain Communities Fire Safe Council, points out the pitch tubes on a pine tree killed by bark beetles on May 12, 2015. The trees use pitch to try to push out parasites. The long drought has weakened many of Idyllwild’s pine trees.(Photo: Richard Lui/The Desert Sun)

Wildfire risks are particularly acute in Idyllwild, a quiet town of several thousand people in the heart of the San Jacinto Mountains, west of the Coachella Valley. Dense pine trees and unruly wildlife cover much of the community, and bark beetles have attacked many of those trees over the past year, priming them to burn.

Idyllwild narrowly escaped the July 2013 Mountain Fire, which charred more than 27,000 acres in the surrounding forest. The fire came within two miles of the Palm Springs Aerial Tramway, blanketing Palm Springs with ash and smoke.

This year, Idyllwild might not be so lucky.

"Common sense tells us that if something is drier, it's more likely to burn," said Edwina Scott, executive director of the Mountain Communities Fire Safe Council, a nonprofit based in Idyllwild.

Already, state fire officials are reporting an uptick in wildfires in 2015.

California saw 1,278 fires through May 9, compared to a five-year average of 757 wildfires over the same time period, according to Cal Fire data — an increase of nearly 70%. This year's wildfires had burned 5,133 acres, compared to a five-year average of 4,805 acres.

Wildfires have always been more frequent and more severe during droughts, said Lynne Tolmachoff, a Cal Fire spokesperson. What's different about this drought is its severity.

"We hope this will be the last summer that we're sitting in this drought," Tolmachoff said. "But we have to prepare for the possibility that we're going to get a fifth or sixth year of drought."

DYING TREES

This isn't the first time bark beetle populations have skyrocketed in Southern California.

The pests killed an enormous number of pine trees in the early 2000s, spurred by drought conditions. Those dead trees stoked the Old Fire, which scorched 90,000 acres in the San Bernardino National Forest in 2003.

In Idyllwild, that bark beetle outbreak was worse than the one underway right now, said Pat Boss, a former Forest Ranger and current project manager at the Mountain Communities Fire Safe Council. But the current outbreak is still getting worse. Boss, who has lived in Idyllwild for more than 60 years, had no trouble pointing out dying pine tree after dying pine tree as he walked down Tollgate Road earlier this week.

"It makes no difference how big the tree is, as far as its vulnerability for the beetle to attack it. Small tree, large tree, it makes no difference," Boss said.

Bark beetles are native to California, and under normal circumstances, they thrive by attacking old, diseased or damaged trees. Healthy pines usually fight them off, trapping the beetles in sticky resin and pushing them out through the bark.

During a drought, many water-stressed trees can't create enough sticky resin to expel the beetles. When that happens, the beetles multiply, sometimes killing a tree within six months.

"They just riddle it, like a shotgun," said Sheri Smith, an entomologist at the U.S. Forest Service in Northern California. "They attack it in multiple locations and overcome the tree."

Drought is killing trees in other ways.

Over the first four months of this year, statewide precipitation is down nearly 60% from the 20th Century average, according to the National Climatic Data Center, and record-low snowpack spurred Gov. Jerry Brown to call for mandatory water cutbacks last month. With so little water to go around, many trees are dying without any help from bark beetles.

In the San Bernardino National Forest, 90 times more trees have been killed by bark beetles this year than were killed in 2013, according to preliminary U.S. Forest Service estimates. In the Angeles National Forest, 150 times more trees have been killed by bark beetles this year than were killed in 2015. In the Cleveland and Los Padres national forests, the differences are even starker.

Overall, more than 12 million trees have died in California's national forests since the drought began, the U.S. Forest Service estimates. For forest managers, it's an enormous but unsurprising number.

"It's no different than your grass, or your trees in the yard," Smith said. "If you run out of water, they die. It's pretty simple."

A tag marks a dead pine tree for removal in Idyllwild on May 12, 2015. Bark beetles have killed many pine trees in this part of the San Jacinto Mountains, in the San Bernardino National Forest.(Photo: Richard Lui/The Desert Sun)

FORESTS ABLAZE

The July 2013 Mountain Fire is still fresh in the minds of many residents in the Coachella Valley, which includes the desert retreat of Palm Springs.

Sparked by an electrical equipment failure in the San Jacinto Mountains, the blaze tore through 22 square miles within two days, threatening the communities of Fern Valley, Idyllwild and Mountain Center. Nearly 6,000 people were ordered to evacuate, and Palm Springs residents were faced with unhealthy air quality as smoke and ash descended into the valley. It took firefighters 16 days, and nearly $26 million, to fully contain the fire. Just a month later, the Silver Fire scorched 20,000 acres.

Two other major wildfires have burned near the Coachella Valley over the past decade. In 2006, the Sawtooth Complex Fire charred about 70,000 acres in the High Desert, threatening Yucca Valley and Pioneertown. A few months later, the arson-caused Esperanza Fire burned more than 40,000 acres in the San Jacinto Mountains and killed five U.S. Forest Service firefighters.

Experts caution that it's difficult to predict wildfires, and that it's impossible to say with certainty how this fire season will compare to previous years. But the increase in dead trees brought on by the drought, experts say, makes it more likely that intense blazes like the Mountain Fire will strike.

The brown needles on this pine tree in Idyllwild on May 12, 2015 indicate a bark beetle infestation. The long drought has weakened the tree’s natural defenses, making it vulnerable to the pests.(Photo: Richard Lui/The Desert Sun)

"Once the tree is dead, it becomes dry, hot-burning fuel for any fire that comes through," Tolmachoff said.

This fire season is already shaping up to be intense.

Fire season typically lasts from June through October, but this year, it's already been underway for more than a month. Cal Fire has already increased staffing to levels that it typically doesn't reach until mid-July, Tolmachoff said. And plants aren't usually as dry as they are now until late June or early July, Rolinski said.